Many commercial applications require precise gauging of holes in a workpiece through which fasteners or other working members are inserted. It is known in the art that when precision of 1/1000th inch is required, such dimensions cannot be gauged by the human eye. It is desirable to have a hand-held, simple to use device which will gauge with the required precision and reduce the level of potential human error imposed by its use. When a multitude of holes are presented in a workpiece, an efficient method for gauging each hole and accurately marking each hole which will require an oversized fastener or other working member is necessary. An example of such an application is where fastener holes in a structural member are coldworked or internally prestressed to offset or mitigate the stress concentrations which fatigue such members. Because coldworking makes no visibly significant change to the workpiece, each such hole must be gauged to determine whether a hole was missed, and therefore undersized, or overworked, and therefore oversized.
The prior means known in the art uses separate undersize and oversize gauges and a separate marking device which is time inefficient and error proned. When it is important that each and every one of a plurality of holes presented to a worker be properly gauged and that any holes which require marking are done so accurately, use of the present invention for such gauging and marking greatly reduces the potential for human error.